‘I don’t really think of myself as the sporty type,’ confesses Shaun Evans. ‘But I’ll have a go at anything.’ Just as well, because the fast-rising actor’s latest starring role, in psychological thriller The Last Weekend, finds him racing bikes, playing golf and dabbling in a spot of tennis – all topped off with a spot of naked swimming/wrestling in the North Sea.

Was that last prospect daunting, given that he was going bottom-to- bottom with co-star Rupert Penry-Jones ? ‘I didn’t let myself think about it,’ he says in his soft Scouse accent. ‘I just dropped my shorts and I was away. You have to trust the director not to make you look like a total t**.’

The Last Weekend marks a change of pace and age for 32-year-old Evans, last seen as the baby-faced pre-Inspector Morse in prequel Endeavour. The tale of a friendship soured by secrets and jealousy, The Last Weekend explores the fracturing relationship between two student mates whose lives have gone separate ways – one’s a primary school teacher, the other a top barrister – yet who still cling to the friendship, complete with annual sporting challenge, that defines their lives. They know they should move on but they’re stuck with who they used to be.

In real life, Evans is lean and boyish, face alight with piercing blue eyes, yet his ability to yo-yo up and down the age scale is evident in The Last Weekend. ‘It’s amazing what a few whiskers will do,’ he says. His character, troubled teacher Ian, is the narrator of the piece, speaking straight to camera as the story unfolds.

‘I like that because you get to see what’s going on in Ian’s mind,’ says Evans. ‘You’re all too aware of how self-aware he is. Here are two friends and they’re in love with the same woman, they have been for years. It leaves Ian with a feeling of failure that runs alongside his sense of competitiveness. You get to see how that plays out.’

The trick that The Last Weekend plays is to leave a question mark hanging over who is the villain of the piece. Faithful to the Blake Morrison novel from which it’s adapted, there’s a creeping sense of foreboding as Ian and Ollie (Penry-Jones) and partners gather at a crumbling country cottage on a stifling summer weekend. ‘It’s a story about who can dominate the other,’ says Evans. ‘It’s animalistic – where does that primal urge to dominate come from?’

There’s a bromance within a bromance going on, with Ian and Ollie’s relationship echoed by Evans and Penry-Jones, who also appear together in hit series Silk and Whitechapel. It was that chemistry that landed Evans the role. ‘Rupert said to me on Silk: “Do you know what you’re doing next?” He’d already signed up for The Last Weekend and thought I’d be perfect for it,’ Evans explains.

He’s been gay teacher John Paul in Teachers, Kurt Cobain on stage and the criminal cousin of Tom Hardy in The Take. But one part he didn’t think was a perfect fit was the Inspector Morse-based Endeavour. ‘I wouldn’t have seen myself in that part,’ he says candidly. ‘To be given it was a massive vote of confidence.’

Was he wary of the responsibility of filling the brogues of one of TV’s most loved characters? ‘Totally but you can’t get caught up in that. You have to bring your own take to it – and I would have been an idiot not to do it,’ he says.

It proved a smart move, with Evans’s buttoned-up Endeavour Morse winning the approval of author Colin Dexter, as well as striking a chord with a wider audience. He’s been signed up to make a further four films, due to screen next year. ‘What I liked was that it wasn’t just aimed at existing Morse fans,’ he says. ‘It was trying for a whole new audience as well.’

Intense and friendly in conversation but hard to crack, Evans seems more happy interviewing me than straying into anything too personal. Admitting he’s a Liverpool fan is about as far as it goes. Evans could be anybody, which is just the way he wants it.